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El-Sayed E.M.M.,Institute of New Materials and Advanced Technology | Zewail T.M.M.,Alexandria University | Zaatout A.A.,Alexandria University
Desalination and Water Treatment

This study aims to the enhancement of Cu2+ ions removal from wastewaters and recovery of the metal value by cementation on a longitudinal finned rotating zinc cylinder. The effect of different parameters such as cylinder rotational speed (rpm), initial Cu2+ ions concentration and the effect of the fin height to cylinder diameter (e/d) on the rate of Cu2+ ions cementation was investigated. In addition, the effect of drag reducing polymer on the rate of Cu2+ cementation was examined. The rate of cementation was expressed in terms of the mass transfer coefficient. The results revealed that the mass transfer coefficient increases with increasing rpm, initial Cu2+ concentration and e/d ratio. The present results show that finned rotating cylinder enhances rate of cementation compared to smooth rotating cylinder by percentage ranges from 28.79 to 134.85 depending on the operating conditions. On the other hand, the presence of drag reducing polymer retards the rate of cementation. The present data fit the following dimensionless equations: For smooth cylinder: Sh = 0.74 Re0.69 Sc0.33. For finned rotating cylinder: Sh = 0.38 Re0.9 Sc0.33 (e/d)0.25. The importance of the above correlations in the design and operation of industrial-scale rotating cylinders cementation reactors was pointed out. © 2015 Balaban Desalination Publications. All rights reserved. Source

Abd El-Latif M.M.,Institute of New Materials and Advanced Technology | Elkady M.F.,Institute of New Materials and Advanced Technology

Harmful ions such as cesium, cobalt and nickel were removed from aqueous solutions using nano zirconium vanadate ion exchangers that prepared using three different techniques and their organic hybrids. Different processing parameters that affect on sorption efficiency were studied. All prepared ion exchangers and their composites have high uptake affinity for cesium removal. The removal capacities of the ion exchangers either the inorganic ones or those that immobilized decreased in the acidic media, in contrast to the alkaline that enhances the ion exchange process. Both the temperature and agitation were found to be appropriate for maximum ions removal. The sorption data obtained for equilibrium conditions have been analyzed using the linear forms of Freundlich, Langmuir and Dubinin-Radushkevich isotherms and the applicability of these isotherm equations to the sorption systems was compared by judging the correlation coefficients, R2. It was established that the equilibrium isotherms models' applicability follows the order: Langmuir > Freundlich > Dubinin-Radushkevich, in case of cesium removal using the different prepared inorganic ion exchangers. But the applicability for cobalt and nickel ions removal using the different prepared inorganic ion exchangers follows the order Freundlich > Langmuir > Dubinin-Radushkevich. The sorption processes for ions uptake using the different types of the prepared inorganic ion exchangers were found to be endothermic processes. © 2010 Elsevier B.V. All rights reserved. Source

El-Maghraby A.,Institute of New Materials and Advanced Technology | El-Deeb H.A.,Institute of New Materials and Advanced Technology
International Journal of Environment and Waste Management

Rice residues are important natural resources, the management of these residues is a major challenge for environment protection. The use of different techniques to produce silica with minimal mineral contaminants having high Specific Surface Area (SSA) has been investigated. The different methods used depended on treatment of rice hulls with different dilute organic acids and hydrochloric acid, without the risk of using corrosive, toxic and hazardous substances in the burning process. Different powdered silica obtained are characterised by particle size distribution, crystallographic structure, BET SSA and chemical analysis. X-ray Diffraction patterns revealed the amorphous nature of silica. The major impurities of silica produced from rice hulls were Na, K and Ca salts. Copyright © 2012 Inderscience Enterprises Ltd. Source

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